JP2007201858A - Crystal resonator, and highly accurate crystal oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crystal resonator with high accuracy and high stability wherein the frequency temperature characteristic is almost flat that achieves downsizing and weight reduction and to provide a highly accurate crystal oscillator. <P>SOLUTION: The crystal resonator 10 includes: a crystal resonator chip 30; a case 20 for housing the crystal resonator reed 30; a thermistor 40 fixed to an inner face of the case 20 and measuring the temperature inside the case 20; and a conductive heating paint 80 coated to the outside surface of the case 20, Heat generating power is supplied to the conductive heating paint 80 on the basis of a measurement value of the thermistor 40 and heat generation by the conductive heating paint 80 controls the crystal resonator reed 30 within a prescribed setting temperature range. The highly accurate crystal oscillator 100 includes the crystal resonator 10 and a control circuit 90 and the highly accurate crystal oscillator 100 whose frequency temperature characteristic is almost flat is realized by managing the crystal resonator 10 within the setting temperature range of a reference temperature or over. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a crystal resonator and a high-accuracy crystal oscillator including the crystal resonator. More specifically, the crystal resonator is provided with a conductive heat-generating paint, and the crystal resonator is held within a temperature range in which the frequency temperature characteristic is substantially flat. The present invention relates to a structure of a crystal resonator and a high-precision crystal oscillator configured as described above.

  Conventionally, a crystal oscillator, which is a frequency control device used in mobile communication equipment and transmission communication equipment, is required to have a flat frequency temperature characteristic over a wide operating temperature range without being affected by external temperature changes. In order to realize such a high-accuracy crystal oscillator, a device that obtains flat frequency temperature characteristics in a constant temperature range by devising the cut angle of the crystal resonator element, and a thermostatic chamber for maintaining the temperature in a certain range Things have been proposed.

  As the cut angle of the quartz crystal resonator piece, the angle formed by the normal line of the quartz plate surface with respect to the new coordinate axis Y ′ axis rotated around the Z axis of the quartz crystal at an angle in the range of the reference angle of 1 degree 30 minutes to 13 degrees. Is known as a quartz crystal resonator using a quartz crystal vibrating piece having a reference angle of 35 degrees 10 minutes to 36 degrees 50 minutes on the AT plate side around the new coordinate axis X ′ axis (for example, Patent Document 1). reference).

  In addition, the plane including the X and Z axes of the crystal is rotated around the Z axis at an angle in the range of 7 degrees to 14 degrees and 40 minutes, and the reference plane on the AT plate side around the new coordinate axis X ′. There is also known a crystal resonator using a crystal vibrating piece cut out with a surface obtained by rotating at an angle in a range of 34 degrees 00 minutes to 35 degrees 10 minutes (excluding 35 degrees 10 minutes) as a main surface. (For example, refer to Patent Document 2).

  Furthermore, the X axis is set to be less than −5.0 degrees or greater than +1 degree (not including 1.0 degree) and rotated by 15.9 degrees or less clockwise around the Z axis of the crystal crystal. It has a side parallel to the X ′ axis, and a side parallel to the Z ′ axis obtained by rotating the Z axis clockwise around the X ′ axis at an angle of 34.6 degrees or more and 35.1 degrees or less. A crystal resonator using a crystal vibrating piece is also known (see, for example, Patent Document 3).

  The thermostat crystal oscillator includes a crystal resonator, a thermostat housing the crystal resonator, and a heater wire disposed in the thermostat, and supplies power to the heater wire. It is known that the temperature of the crystal unit is controlled within a certain temperature range by generating heat at the temperature (for example, see Patent Document 4).

Japanese Patent Laid-Open No. 10-284978 JP 2003-324332 A JP 2004-7420 A JP 2001-16034 A

  According to Patent Documents 1 to 3 as described above, the frequency temperature characteristic is substantially flat in a region higher than the reference temperature (sometimes referred to as normal temperature), and excellent frequency temperature characteristics are exhibited in a certain temperature range. It is. However, in the low temperature region below the reference temperature, the frequency temperature characteristic has a large displacement width and satisfactory characteristics cannot be obtained, and there is a problem that it cannot cope with a wide range of operating temperature environments.

  As a method for solving such a problem, there is a problem that a temperature compensation circuit must be provided on a lower temperature side than the reference temperature.

  In addition, in the thermostatic chamber type crystal oscillator, it is intended to realize a structure that is less affected by the external temperature by accommodating the crystal resonator in the thermostatic chamber. The structure becomes complicated, which makes it difficult to reduce the size and weight, and increases the cost.

  SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems, and without using a temperature compensation circuit in a low temperature region, realizes high accuracy, high stability, miniaturization, and weight reduction with a substantially flat frequency temperature characteristic. To provide a crystal resonator and a high-precision crystal oscillator.

The crystal resonator according to the present invention includes a crystal resonator element, a case that accommodates the crystal resonator element, a thermosensitive element that is fixed to the inner surface of the case and measures the temperature inside the case, and an outer side of the case. A heat generating member including a conductive heat generating paint provided on the surface, supplying heat generation power to the conductive heat generating paint based on the measured value of the temperature sensing element, and the crystal vibrating piece is predetermined by the heat generated by the heat generating member. The temperature is controlled within the set temperature range.
Here, as the conductive heat-generating paint, for example, a material in which an organic natural polymer adhesive containing fine powder of conductive carbon allotrope and moisture is mixed can be employed.

  According to the present invention, the conductive heat generating paint is adopted as the heat generating material, the conductive heat generating paint is heated to a predetermined set temperature range, and the temperature of the crystal unit is controlled, so that the influence of the external temperature is small. A highly accurate frequency characteristic can be obtained. Furthermore, the structure can be simplified as compared with the above-described constant-temperature bath type crystal oscillator, and this makes it possible to reduce the weight and size.

  In addition, since conductive heat-generating paint is used as the heat generating material, it can be easily formed on the outer surface of the case by means such as coating, regardless of the shape of the crystal unit as the heating target member, that is, the shape of the case. There is an effect that it can be formed.

Further, there is an effect that the thickness, application area, and application shape of the conductive heat-generating paint can be arbitrarily set in accordance with the range and level of the set temperature.
Further, since the conductive heat-generating paint is formed on the outer surface of the case, there is an effect that the vibration of the crystal unit due to the gas and moisture considered to be generated from the conductive heat-generating paint is not affected.

  Further, since the temperature sensitive element is fixed to the inner surface of the case, the temperature inside the case, that is, the temperature of the crystal vibrating piece can be accurately measured. If the temperature sensitive element is a thermistor, it is known that the thermistor is vulnerable to deformation. However, since the thermistor is provided inside the case, it is difficult to be affected by deformation or the like and can maintain good performance.

The quartz crystal resonator element rotates at a predetermined angle around the Z axis of the crystal crystal having the orthogonal coordinate axes X, Y, and Z as crystal axes, and further rotates at a predetermined angle around the new coordinate axis X ′. When the quartz crystal resonator element is a twice-rotated quartz crystal resonator, the frequency temperature characteristic is substantially flat in a region higher than the reference temperature, and when the frequency temperature property is in a region lower than the reference temperature, It is preferable to control the piece to a predetermined set temperature range higher than the reference temperature.
Here, the reference temperature means a temperature around 25 ° C., which is generally room temperature. Moreover, as a 2 times rotation quartz-crystal vibrating piece, the quartz-crystal vibrating piece cut out by the cut angle shown in patent document 1-patent document 3 mentioned above, for example is contained.

  It is known that the quartz crystal resonator element cut out with the cut angle as described above has a region where the frequency temperature characteristic is substantially flat in a temperature region higher than the reference temperature. Here, when the temperature is lower than the reference temperature, the conductive heat-generating paint is heated to maintain the crystal resonator to a predetermined set temperature range higher than the reference temperature, thereby using a temperature compensation circuit in a low temperature range. Therefore, it is possible to provide a high-accuracy crystal resonator having a substantially flat frequency temperature characteristic that is not affected by the external temperature environment.

  Moreover, it is preferable that the conductive exothermic paint is directly coated on the outer surface of the case.

Since the conductive heat-generating paint having the above-described structure can be used, it can be easily formed on the case surface by means such as coating. In this way, it is possible to form a heat generating member on the case surface regardless of the shape of the case, the structure can be further simplified, and a slight increase in thickness of the case surface can be achieved, thereby realizing a reduction in weight and size. .
Further, there is an effect that the thickness, application area, and application shape of the conductive heat-generating paint can be arbitrarily set in accordance with the range and level of the set temperature.

  Furthermore, it is preferable that the heat generating member includes a base member and the conductive heat generating paint coated on a surface of the base member, and the heat generating member is attached to the case.

Since the heat generating member forms the heat generating member by covering the surface of the base member separate from the crystal resonator with the conductive heat generating paint, there is an effect that the covering operation becomes easy.
The base member may be a sheet shape or a cap shape, and can be arbitrarily selected. Further, as the material of the base member, it is more preferable to select a material having good thermal conductivity and fix it with an adhesive having good thermal conductivity.

The temperature sensitive element is preferably a PTC thermistor.
A PTC (Positive Temperature Coefficient Thermistor) thermistor is an element that can measure temperature from a change in electrical resistance with a minute voltage that does not involve self-heating due to Joule heat. Enables accurate temperature measurement.

  The high-precision crystal oscillator of the present invention includes a crystal resonator configured as described above, an oscillation circuit that controls excitation of the crystal resonator, a temperature control circuit that controls temperature measurement by a temperature-sensitive element, And a voltage control circuit that supplies heat generation power to the conductive heat generation paint based on a signal from the temperature control circuit.

  According to the present invention, when the temperature is lower than the reference temperature, the conductive heat-generating paint is heated to maintain the crystal resonator to a predetermined set temperature range higher than the reference temperature. It is possible to provide a high-accuracy crystal oscillator having a substantially flat frequency temperature characteristic that is not affected.

  Further, the structure can be simplified as compared with a conventional crystal oscillator using a temperature compensation circuit in a low temperature region or a conventional thermostatic chamber crystal oscillator, and thus, weight reduction and downsizing can be realized.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show the structure of a crystal resonator according to Embodiment 1 of the present invention, FIGS. 3 to 8 show typical two-turn cut crystal resonator elements and their frequency-temperature characteristics, and FIG. 9 shows the embodiment. FIG. 10 shows a second embodiment, and FIG. 11 shows a schematic configuration of a high-precision crystal oscillator of the present invention.
(Embodiment 1)

  1A and 1B schematically show the structure of a crystal resonator according to the first embodiment. FIG. 1A is a perspective view showing a state seen through a lid, and FIG. It is sectional drawing of -A cut surface. 1A and 1B, a crystal resonator 10 houses a crystal vibrating piece 30 and a thermistor 40 as a temperature sensitive element inside a box-shaped case 20, and conductive heat generation on the case back surface 24. A paint 80 is formed and configured.

  The case 20 is formed of ceramics, and a base portion 21 formed in a step shape is provided inside. The base portion (not shown) of the crystal vibrating piece 30 is fixed to the base portion 21. Yes. A thermistor 40 is fixed to the bottom 22 inside the case 20.

  In the state where the crystal vibrating piece 30 and the thermistor 40 are housed, the opening of the case 20 is hermetically sealed by the lid 50. The space 23 formed by the case 20 and the lid 50 is in a high vacuum state.

  The quartz crystal vibrating piece 30 is connected to a lead electrode (not shown), and the lead electrode extends to the back surface 24 of the case and is connected to the in / out terminals 61 and 63, the GND terminal 62, and the Vcc terminal 64 (see also FIG. 2). To do). Further, two electrodes 71 and 72 are formed on the surface of the case back surface 24, and a conductive heat generating paint 80 is formed on the surface of the electrodes 71 and 72 and the case back surface 24.

  The constituent material of the conductive heat-generating paint 80 is not particularly limited, but in this embodiment, the conductive natural carbon polymer fine powder and water-containing organic natural polymer binder are used as constituent elements. Yes. Specific examples of carbon allotropes include graphite powder (graphite) or carbon powder (carbon black), and organic natural polymer binders include paste (generally called starch paste). Moreover, in order to obtain a target resistance value, a resistance agent such as silicon carbide may be mixed.

  Next, a method for coating the conductive heat generating paint 80 will be described. The conductive exothermic paint 80 prepared by mixing and adjusting the above-mentioned fine carbon allotrope powder, moisture-containing organic natural polymer binder, and resistance agent is applied to the back surface 24 of the case. As an application method, brush coating, spraying, or the like can be employed. After application, the film is naturally dried to keep the thickness of the coating film constant.

Next, the arrangement relationship of the crystal vibrating piece 30, the thermistor 40, and the conductive heat generating paint 80 will be described.
FIG. 2 is an explanatory plan view in which the case back surface 24 side of the crystal unit 10 is visually recognized. In FIG. 2, in / out terminals 61 and 63, a GND terminal 62, and a Vcc terminal 64 are formed in the four corner directions of the case back surface 24. The GND terminal 62 is connected to an electrode 71 as one heating electrode through a lead electrode 75.

  The thermistor 40 is connected to a Vcc terminal 64 and an electrode 72 as the other heating electrode. The conductive heat generating paint 80 is formed in a range that does not contact the in / out terminals 61 and 63, the GND terminal 62, and the Vcc terminal 64, and the ends of the electrodes 71 and 72 are exposed. In the exposed portions, the thermistor 40 and the lead are formed. It is connected to the electrode 75 (that is, the GND terminal 62).

  The thermistor 40 may be connected with two terminals drawn out of the case 20 and connected to the electrode 72 and the Vcc terminal 64 on the case back surface 24, and one terminal connected to the Vcc terminal 64 inside the case 20. The lead electrode to be connected may be connected, and the other terminal may be led to the case back surface 24 by the lead electrode and connected to the electrode 72.

Subsequently, a typical example of the twice-rotation cut quartz crystal vibrating piece will be given, and the relationship between the cut angle and the frequency temperature characteristic and the operation of the present invention will be described with reference to the drawings.
FIG. 3 is an explanatory view showing a cut angle of the two-time rotation cut quartz crystal vibrating piece proposed in Patent Document 1 described above. This quartz crystal resonator is rotated with respect to a new coordinate axis Y′-axis rotated at an angle φ1 in the range of a reference angle of 1 degree 30 minutes to 13 degrees around the Z-axis of the crystal crystal having orthogonal coordinate axes X, Y, Z as crystal axes. The quartz crystal resonator element is used in which the angle φ2 formed by the normal line of the quartz plate surface is cut around the new coordinate axis X ′ axis in the range of the reference angle of 35 ° 10 minutes to 36 ° 50 minutes on the AT plate side.

From this cut angle range, φ1, large, medium and small are selected to show frequency temperature characteristics.
FIG. 4 is a graph showing frequency temperature characteristics in which Δf / f is normalized to 0 when the reference temperature Tp is 25 ° C. (sometimes referred to as normal temperature). The horizontal axis shows temperature (° C.), and the vertical axis shows frequency temperature characteristics (Δf / f, ppm). Here, the graph represents a case where φ1 is set to 1 degree 30 minutes, B is 7 degrees, and C is 13 degrees.

  As shown in FIG. 4, at each cut angle, the frequency temperature characteristic Δf / f is flatter than the low temperature region in the range from the reference temperature of 25 ° C. to + 80 ° C., and is in the target range of 5 ppm. In the region where the reference temperature is 25 ° C. or less, the frequency temperature characteristic Δf / f is 5 ppm or more.

  FIG. 5 is an explanatory view showing the cut angle of the two-turn cut quartz crystal vibrating piece proposed in Patent Document 2 described above. This crystal resonator rotates around the Z axis of the crystal crystal having the orthogonal coordinate axes X, Y, Z as crystal axes at an angle φ1 in the range of 7 degrees to 14 degrees 40 minutes, and a new coordinate axis X ′. It is composed of a quartz plate cut out with the surface obtained by rotating around the axis at an angle within the range of 34 degrees to 35 degrees and 10 minutes (excluding 35 degrees and 10 minutes) as the main surface on the AT plate side. In addition, a two-turn cut quartz crystal vibrating piece is used.

From this cut angle range, φ1, large, medium and small are selected to show frequency temperature characteristics.
FIG. 6 is a graph showing frequency temperature characteristics in which Δf / f is normalized to 0 when the reference temperature Tp is 25 ° C. The horizontal axis shows temperature (° C.), and the vertical axis shows frequency temperature characteristics (Δf / f, ppm). The individual graphs show the case where φ1 is 7 degrees, E is 12 degrees, and F is 14 degrees.

  As shown in FIG. 6, at each cut angle, in the region from the reference temperature of 25 ° C. to + 80 ° C., the frequency temperature characteristic Δf / f is flatter than the low temperature region and is in the target 5 ppm range, In the region where the reference temperature is 25 ° C. or less, the frequency temperature characteristic Δf / f is 5 ppm or more.

  FIG. 7 is an explanatory diagram showing the cut angle of the two-turn cut quartz crystal vibrating piece proposed in Patent Document 3 described above. In this crystal resonator, the angle φ is greater than or equal to −5 degrees and less than or equal to −1 degree, or greater than +1 degree in the clockwise direction around the Z axis of the crystal crystal having the orthogonal coordinate axes X, Y, and Z as crystal axes. And has a side parallel to the X ′ axis set by rotating it by 15.9 degrees or less, and the angle θ of the Z axis in the clockwise direction around the X ′ axis is 34.6 degrees or more, and 35.1 A crystal plate having a side parallel to the Z ′ axis rotated by less than 1 degree, or an angle φ of the X axis in the clockwise direction around the Z axis is rotated from −15.9 degrees to −5 degrees. The Z ′ axis has a side parallel to the set X ′ axis and the angle θ of the Z axis in the clockwise direction around the X ′ axis is 34.2 degrees or more and rotated by 35.3 degrees or less. A quartz crystal vibrating piece cut out with parallel sides is used.

The frequency temperature characteristic is shown by selecting large or small φ from this cut angle range.
FIG. 8 is a graph showing frequency temperature characteristics in which Δf / f is normalized to 0 when the reference temperature Tp is 25 ° C. The horizontal axis shows temperature (° C.), and the vertical axis shows frequency temperature characteristics (Δf / f, ppm). Here, the graph represents a case where θ = 34.7 degrees, φ1, G is 8.3 degrees, and H is 12 degrees.

  As shown in FIG. 8, at each cut angle, the frequency temperature characteristic Δf / f is flat in the region from the reference temperature of 25 ° C. to + 80 ° C. compared to the low temperature region, and is in the target range of 5 ppm. . In the region where the reference temperature is 25 ° C. or less, the frequency temperature characteristic Δf / f is 5 ppm or more.

  The frequency temperature characteristics Δf / f of the cut angles described above both show 5 ppm or less in the reference temperature range of 25 ° C. to 80 ° C., and both do not satisfy the target value of 5 ppm or less in the region where the reference temperature is 25 degrees or less. . Therefore, when the operating temperature environment is equal to or lower than the reference temperature, if the crystal resonator is heated and maintained at the reference temperature of 25 ° C. to 80 ° C. (when 80 ° C. is the upper limit of the operating temperature range), the frequency temperature characteristic Δf / f In the range of 5 ppm.

  Next, the heating maintenance action of the crystal resonator in the present embodiment will be described with reference to FIG. The crystal resonator 10 includes a crystal vibrating piece 30, a thermistor 40, and a conductive heat generating paint 80 as a heat generating member. The temperature in the case 20 is measured by the thermistor 40 and the temperature control circuit 93. When the temperature is equal to or lower than the reference temperature, the difference between the temperature to be raised and the power to be supplied are calculated based on the measurement result.

  Based on the result, a necessary voltage is applied from the voltage control circuit 92 to the conductive heat generating paint 80. When the thermistor 40 detects that the set temperature range has been reached, the voltage application to the conductive heat-generating paint 80 is stopped. By repeating this, the quartz vibrating piece 30 is maintained and controlled within a temperature range in which the target frequency temperature characteristic Δf / f can be obtained.

  In the present invention, if the upper limit of the operating temperature range is + 80 ° C., the temperature management range may be the reference temperature 25 ° C. to 80 ° C. Therefore, the temperature management range is wide and can be easily managed.

  In the present embodiment, it is preferable to employ a PTC thermistor as the thermistor 40. The PTC thermistor is preferable because it is a temperature-sensitive element capable of measuring temperature from a change in electrical resistance with a minute voltage that does not involve self-heating due to Joule heat.

  Therefore, according to the first embodiment, the quartz crystal vibrating piece 30 cut out by the two-time rotation cut proposed in Patent Documents 1 to 3 described above has a frequency temperature characteristic Δf in a temperature region higher than the reference temperature 25 ° C. There is a region where / f is small. However, satisfactory frequency temperature characteristics cannot be obtained at a reference temperature of 25 ° C. or lower. Therefore, when the temperature is lower than the reference temperature of 25 ° C., the conductive heat generating paint 80 is heated to heat the crystal vibrating piece 30 to a predetermined set temperature range of 80 ° C. higher than the reference temperature. By maintaining the range, it is possible to provide a high-accuracy crystal resonator having a substantially flat frequency temperature characteristic that is not affected by the external temperature environment without using a temperature compensation circuit in a low temperature region.

  In addition, since the structure can be simplified as compared to the above-described constant-temperature bath type crystal oscillator, it is possible to realize weight reduction, size reduction, and cost reduction.

The conductive heat generating paint 80 can be easily formed on the surface of the case 20 by means such as coating. Therefore, there is an effect that the conductive heat generating paint 80 can be formed on the surface of the case 20 regardless of the shape of the case 20.
Further, there is an effect that the thickness, application area, and application shape of the conductive heat generating paint 80 can be arbitrarily set in accordance with the range and level of the set temperature.

  Further, since the thermistor 40 is fixed to the inner surface of the case 20, the temperature inside the case 20, that is, the temperature of the crystal vibrating piece 30 can be accurately measured. The thermistor 40 is known to be susceptible to deformation. However, since the thermistor 40 is provided inside the case 20, the thermistor 40 is not easily affected by deformation or the like and can maintain good performance.

In addition, the TPC thermistor can measure the temperature from the change in electric resistance with a minute voltage that does not cause self-heating due to Joule heat, and the TPC thermistor has a positive temperature-resistance characteristic. Furthermore, since the frequency temperature characteristics in the low temperature region shown in FIGS. 4, 6 and 8 show positive characteristics, it can be estimated that the arithmetic processing becomes easy.
(Modification of Embodiment 1)

Subsequently, a modification of the crystal resonator according to the first embodiment of the present invention will be described with reference to the drawings. This modification is characterized in that the formation range of the conductive heat-generating paint is changed with respect to the first embodiment (see FIGS. 1 and 2). Since others are the same as Embodiment 1, description is abbreviate | omitted.
FIG. 9 is a cross-sectional view schematically showing a modification of the first embodiment. FIG. 9A shows a first modification, and FIG. 9B shows a second modification.

  First, Modification 1 will be described. The first modification is characterized in that the conductive heat generating paint 80 is formed over the case back surface 24 and the side surface 25. The in / out terminals 61 and 63, the GND terminal 62, and the Vcc terminal 64 (see FIG. 2) formed on the case back surface 24 are not shown, but the conductive heating paint 80 opens these terminals. Formed.

  The modification 2 is characterized in that the conductive heat-generating paint 80 is formed over the case back surface 24, the side surface 25, and the surface of the lid 50. The conductive heat generating paint 80 can be formed by coating the entire surface of the quartz crystal resonator 10 after packaging.

  In addition, it is not restricted to the modifications 1 and 2 mentioned above, The formation range of the conductive exothermic paint 80 is free with the thickness.

According to such modifications 1 and 2, since the formation area of the conductive heat-generating paint 80 is widened and the periphery of the crystal unit 10 can be covered widely, the response to temperature rise can be enhanced.
(Embodiment 2)

Subsequently, a crystal resonator according to a second embodiment of the present invention will be described with reference to the drawings. In the present embodiment, while the conductive heat generating paint 80 is directly formed on the case 20 in the first embodiment, a heat generating member in which the conductive heat generating paint 80 is formed on the base member is attached to the case 20. It has the feature in being. Only the differences will be described. Other common parts are denoted by the same reference numerals.
FIG. 10 schematically shows the crystal resonator according to the present embodiment, where (a) is a cross-sectional view and (b) is a plan view of the case back surface 24 visually recognized.

  The crystal unit 10 is configured by packaging a heat generating member 85 on the case back surface 24 after packaging. The heat generating member 85 includes an insulating sheet 86 as a base member, electrodes 71 and 72 formed on the surface of the sheet 86, and a conductive heat generating paint 80 formed on the surface of the sheet 86 including these electrodes. It is composed of

  As shown in FIG. 10B, both ends of the electrodes 71 and 72 are partially exposed from the peripheral edge of the conductive heat-generating paint 80. One end of the electrode 71 is connected to the lead electrode 75 extending from the GND terminal 62 using a conductive adhesive or the like. Also, one end of the electrode 72 is connected to a lead electrode extending from the thermistor 40 using a conductive adhesive or the like.

  The heat generating member 85 including the conductive heat generating paint 80 may have a shape as shown in FIG. 10B, or may have a shape that extends to the side surface 25 of the case 20.

  Although not shown, the base member can be a cap that is more rigid than the sheet 86. As a cap, it can be set as the box shape which can be mounted | worn with the case 20, and it can be set as the structure which forms the electrode and the conductive heat-generation coating material 80 on the surface, and affixes on the case 20. In such a structure, the conductive heat-generating paint 80 can be formed on the inner side or the outer side of the cap.

  According to the second embodiment, since the heat generating member 85 is formed by applying the conductive heat generating paint 80 to the surface of the sheet 86 or the cap that is separate from the case 20, there is an effect that the application work becomes easy. is there.

A plurality of types of heat generating members 85 corresponding to the predetermined frequency temperature characteristics and management temperature region of the crystal oscillator in which the material, thickness, application area, etc. of the conductive heat generating paint 80 are set are prepared. By selecting and mounting the heat generating member 85 according to the 10 setting specifications, it becomes possible to easily provide a desired high-precision crystal resonator, which contributes to a reduction in manufacturing cost.
(High-precision crystal oscillator)

Subsequently, a high-precision crystal oscillator including the crystal resonator 10 according to Embodiment 1 or Embodiment 2 described above will be described.
FIG. 11 is a configuration diagram showing the main configuration of the high-precision crystal oscillator of the present invention. The high-accuracy crystal oscillator 100 is composed of the crystal resonator 10 and the control circuit 90 described above.

  The control circuit 90 includes an oscillation circuit 91 that controls excitation of the crystal vibrating piece 30, a temperature control circuit 93 that controls temperature measurement by the thermistor 40, and a heat generation power applied to the conductive heating paint 80 based on a signal from the temperature control circuit 93. Is integrated into one chip by a semiconductor device including a voltage control circuit 92 for supplying the signal.

  When such a high-precision crystal oscillator 100 is in a temperature range lower than the reference temperature of 25 ° C., the conductive heat generating paint 80 generates heat to cause the crystal unit 10 to have a predetermined set temperature of 80 ° C. higher than the reference temperature of 25 ° C. By heating and maintaining the temperature within the range, it is possible to provide a high-precision crystal oscillator 100 having a substantially flat frequency temperature characteristic that is not affected by the external temperature environment.

  Further, the structure can be simplified as compared with a conventional crystal oscillator using a temperature compensation circuit in a low temperature region or a conventional thermostatic chamber crystal oscillator, and thus, weight reduction and downsizing can be realized.

It should be noted that the present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved.
That is, although the present invention has been illustrated and described with particular reference to particular embodiments, it is not intended to depart from the technical spirit and scope of the invention. Various modifications can be made by those skilled in the art in terms of materials, combinations, other detailed configurations, and processing methods between manufacturing processes.

  For example, in the above-described embodiment, the electrodes 71 and 72 for supplying electric power to the conductive heat generating paint 80 are provided, but the electrodes 71 and 72 can be omitted. That is, one terminal of the lead electrode 75 and the thermistor 40 may be directly connected to the conductive heat generating paint 80.

  Therefore, according to the present invention described above, it is possible to provide a crystal oscillator and a high-accuracy crystal oscillator that achieves a highly accurate and highly stable frequency temperature characteristic that is substantially flat, and that can be reduced in size and weight.

BRIEF DESCRIPTION OF THE DRAWINGS The structure of the crystal oscillator concerning Embodiment 1 of this invention is shown typically, (a) is a perspective view, (b) is sectional drawing of the AA cut surface of (a). FIG. 3 is an explanatory plan view of the crystal case according to the first embodiment of the present invention when the case back surface is visually confirmed. Explanatory drawing which shows the cut angle of the 2 times rotation cut quartz crystal vibrating piece by a prior art (patent document 1). The graph which shows the frequency temperature characteristic of patent document 1. FIG. Explanatory drawing which shows the cut angle of the 2 times rotation cut quartz crystal vibrating piece by a prior art (patent document 2). The graph which shows the frequency temperature characteristic of patent document 2. FIG. Explanatory drawing which shows the cut angle of the 2 times rotation cut quartz crystal vibrating piece by a prior art (patent document 3). The graph which shows the frequency temperature characteristic of patent document 3. FIG. Sectional drawing which shows typically the modification of the crystal resonator which concerns on Embodiment 1 of this invention. The crystal resonator which concerns on Embodiment 2 of this invention is shown typically, (a) is sectional drawing, (b) is the top view which visually recognized the case back surface. The block diagram which shows the main structures of the high precision crystal oscillator of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Crystal oscillator, 20 ... Case, 24 ... Case back surface, 30 ... Crystal vibrating piece, 40 ... Thermistor, 80 ... Conductive heating paint, 90 ... Control circuit, 100 ... High precision crystal oscillator.

Claims (6)

A crystal vibrating piece, a case for housing the crystal vibrating piece,
A temperature sensitive element that is fixed to the inner surface of the case and measures the temperature inside the case;
A heating member including a conductive heating paint provided on the outer surface of the case, and
A crystal resonator, wherein heat generation power is supplied to the conductive heat generating paint based on a measured value of the temperature sensing element, and the crystal vibrating piece is controlled within a predetermined set temperature range by heat generation of the heat generating member. The crystal resonator according to claim 1,
The crystal vibrating piece is rotated twice at a predetermined angle around the Z axis of the crystal crystal having the orthogonal coordinate axes X, Y, Z as crystal axes, and further rotated at a predetermined angle around the new coordinate axis X ′. It is a rotating quartz crystal vibrating piece, and has a substantially flat characteristic in a region where the frequency temperature characteristic is higher than the reference temperature.
A quartz resonator, wherein the quartz resonator element is controlled to a predetermined set temperature range higher than a reference temperature by heat generation of the conductive heat-generating paint when in a region lower than a reference temperature. In the crystal unit according to claim 1 or 2,
A crystal resonator, wherein the conductive heat-generating paint is directly coated on an outer surface of the case. In the crystal unit according to claim 1 or 2,
The heat generating member comprises a base member, and the conductive heat generating paint coated on the surface of the base member,
A crystal resonator, wherein the heat generating member is attached to the case. In the crystal unit according to any one of claims 1 to 4,
The quartz resonator, wherein the temperature sensitive element is a PTC thermistor. A crystal resonator according to any one of claims 1 to 5, and
An oscillation circuit for controlling excitation of the crystal resonator;
A temperature control circuit for controlling temperature measurement by the temperature sensing element;
A voltage control circuit that supplies heat generation power to the conductive heat generation paint based on the signal of the temperature control circuit;
A high-precision crystal oscillator characterized by comprising:

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